open_acm · ACM MCP Server MCP: Risk & Policy

WHAT IT DOES

What open_acm does on ACM MCP Server

AI agents invoke open_acm to trigger actions in ACM MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why open_acm needs a policy

This tool launches an external application (ACM) and creates a new COM session, triggering an external operation beyond simple data reads or writes. It initiates a process/session in Aspen Custom Modeler, which constitutes executing an external operation. Severity is medium because misuse could open unintended files or consume system resources, but it doesn't directly delete data or move money.

From the tool's definition Open an .acmf file in ACM and create a session

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

open_acm Rate-limited

open_acm stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "open_acm": {
      "limits": [
        {
          "counter": "open_acm_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches ACM MCP Server, so you can run agents against it safely.

FAQ

Questions about open_acm

What does the open_acm tool do? +

Open an .acmf file in ACM and create a session. It is categorised as a Execute tool in the ACM MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on open_acm? +

Register the ACM MCP Server MCP server in PolicyLayer and add a rule for open_acm: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches ACM MCP Server. Nothing to install.

What risk level is open_acm? +

open_acm is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit open_acm? +

Yes. Add a rate_limit block to the open_acm rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block open_acm completely? +

Set action: deny in the PolicyLayer policy for open_acm. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides open_acm? +

open_acm is provided by the ACM MCP Server MCP server (pekosann/acm-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.